Study for the design and construction of high resolution gratings
(Comunidad de Madrid grant in collaboration with FRACTAL)
UCM is currently collaborating on a project funded by the Comunidad de Madrid (Consejería de Comercio e Industria, exp. 22/2009) in collaboration with FRACTAL S.L.N.E. The goal is to explore segmented-pupil gratings to increase the spectral resolution of instruments without modifying their geometry either envelope. The 2009 project ends with the building of a real prototype for R=10.000 and a pupil diameter of 89mm. UCM and FRACTAL are now working on a more ambitious project with the final goal of building a new sliced-pupil prototype whose size and resolution fit MEGARA specification (162mm pupil diameter and R=17.000).
Sliced Pupil Grating manufacturing process
The two mother bars after cutting at the polisher facilities. Three identical prisms shall be polished from each bar. Next phase is entering the polishing process of the last surface (viewA) which is the one with tigher SFE specification. The polishing phase is indeed the critical step for us as the mother bars are very long and thin.
Pictures of the mother blank in the pre-polishing phase before cutting the prisms (provided bySESO).The two opposite surfaces are now in an advanced polishing phase until they meet specifications. The chip visible on one side won’t have any effect on the final prisms as it will disappear with the cutting on the mother prisms.
Expand the thumbnails to see the grating holders as provided by FRACTAL and the VPH already mounted.
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